A comparison of MR elastography and 31P MR spectroscopy with histological staging of liver fibrosis

Objectives Conventional imaging techniques are insensitive to liver fibrosis. This study assesses the diagnostic accuracy of MR elastography (MRE) stiffness values and the ratio of phosphomonoesters (PME)/phosphodiesters (PDE) measured using P-31 spectroscopy against histological fibrosis staging. Methods The local research ethics committee approved this prospective, blinded study. A total of 77 consecutive patients (55 male, aged 49 +/- 11.5 years) with a clinical suspicion of liver fibrosis underwent an MR examination with a liver biopsy later the same day. Patients underwent MRE and P-31 spectroscopy on a 1.5 T whole body system. The liver biopsies were staged using an Ishak score for chronic hepatitis or a modified NAS fibrosis score for fatty liver disease. Results MRE increased with and was positively associated with fibrosis stage (Spearman's rank = 0.622, P < 0.001). PME/PDE was not associated with fibrosis stage (Spearman's rank = -0.041, p = 0.741). Area under receiver operating curves for MRE stiffness values were high (range 0.75-0.97). The diagnostic utility of PME/PDE was no better than chance (range 0.44-0.58). Conclusions MRE-estimated liver stiffness increases with fibrosis stage and is able to dichotomise fibrosis stage groupings. We did not find a relationship between P-31 MR spectroscopy and fibrosis stage.